2.4Lesson 2.4: JavaScript outside the browser: Node.js

The idea

Until now, JavaScript ran in the browser. Node.js runs it on your computer, from the terminal, from a file.

The language is the same. And it's what many servers use: you'll see it again in Back end.

Installing it

Download the LTS version from nodejs.org and install it. LTS means long-term support: it's the stable one.

Check it's there, in a new terminal:

$ node --version

v24.11.0

Your number may be different. What matters is that one shows up.

Running a file

In the VS Code terminal, already in my-game:

$ node hello.js

Hello from a file

node followed by the file's path. Since you're in its folder, the name is enough.

What Node doesn't have

prompt() and alert() belong to the browser: they open windows, and the terminal has no windows. In Node they give an error:

ReferenceError: prompt is not defined

console.log() does work: it writes to the terminal.

Try it

$ node table.js

3 x 1 = 3
3 x 2 = 6
…
3 x 10 = 30

Summary

• Node.js runs JavaScript outside the browser.
• node file.js runs a file.
• prompt() and alert() don't exist in Node; console.log() does.